Oxidising Power and Displacement — Displacement
Displacement is the practical redox test of halogen oxidising power: a more reactive halogen X₂ oxidises the halide of a less reactive halog
Learning objectives
- Explain Oxidising Power and Displacement — Displacement using Group 17 language.
- Link trends to size, shielding, forces and bond strength.
- Apply equations and observations in FBISE-style answers.
Definition
Displacement is the practical redox test of halogen oxidising power: a more reactive halogen X₂ oxidises the halide of a less reactive halogen. Cl₂ displaces Br⁻ and I⁻; Br₂ displaces I⁻; I₂ does not displace Cl⁻ or Br⁻.
Core Concept
Cl₂ + 2Br⁻ → 2Cl⁻ + Br₂ (orange) Cl₂ + 2I⁻ → 2Cl⁻ + I₂ (brown/violet) Br₂ + 2I⁻ → 2Br⁻ + I₂ I₂ + Cl⁻/Br⁻ → no reaction Parent: Oxidising Power and Displacement
Beginner
Stronger halogen pushes out weaker halide. Cl₂ can make Br₂ or I₂ appear; Br₂ can make I₂ appear; I₂ cannot make Cl₂ or Br₂.
Intermediate
Memorise the three working equations and the no-reaction case. Attach colours to products.
Advanced
Displacement is a competition for electrons between X₂X⁻ couples. The higher couple oxidises the lower halide.
Remember
Cl₂→Br⁻,I⁻ · Br₂→I⁻ · I₂↛Cl⁻,Br⁻ · equations + colours · parent oxidising topic.
Exam preparation
Exam Focus
Quick revision
Revision Zone
Oxidising Power and Displacement — Displacement
Sticky Notes · Quick Revision
Works
- Cl₂ with Br⁻ or I⁻
- Br₂ with I⁻
Fails
- I₂ with Cl⁻
- I₂ with Br⁻
Colours
- Br₂ orange
- I₂ brown/violet
Parent
- oxidising power and displacement
- displacement
60-second revision
- Cl₂ displaces Br⁻ and I⁻; Br₂ displaces I⁻; I₂ displaces neither Cl⁻ nor Br⁻.
- Ionic equations + colours.
- Subtopic of oxidising power and displacement.
Did you understand this topic?
Your answer is saved with your learning record. It does not mark the topic as mastered.